Explanation

Near Earth's surface, the acceleration due to gravity (g) is approximately 10 meters per second squared (10 ms^-2).

This is a fundamental constant that describes the strength of gravity on our planet.

Explanation

Distance is a scalar quantity because it only has magnitude (amount of length) but no direction.

Distance is a measure of how far apart two points are, but it doesn't have a direction.

Explanation

Centrifugal force is a fictitious force that appears to act on an object moving in a circular path, causing it to move away from the center of the circle.

It is a result of the inertia of the object, which tends to keep it moving in a straight line.

Explanation

A spring balance is a device used to measure the weight of an object.

It consists of a spring that is stretched or compressed by the weight of the object, and a pointer or dial that indicates the weight.

Explanation

The vertical component of the force is:

Vertical component = Force × sin(angle)

= 15 N × sin(60°)

= 15 N × 0.866

= 13 N

So, the vertical component of the 15 N force at an angle of 60° is approximately 13 N.

Explanation

In a solid, the particles (atoms, molecules, or ions) are closely packed and vibrate in place, holding their position in the crystal lattice.

This vibration is due to thermal energy, and the particles oscillate around their fixed positions.

Key Points:

• In a gas, particles are widely spaced and move freely.
• In a liquid, particles are close together but move past each other.

Explanation

Limiting frictional force (also known as static friction) is greater than:

• Rolling friction (because rolling friction is much smaller, as it only opposes the motion of an object that is already rolling)
• Sliding friction (which is another term for kinetic friction)
• Kinetic friction (which is the frictional force that acts when an object is already moving)

Explanation

Significant figures (also known as significant digits) are the number of digits in a measurement or calculation that are known to be reliable and accurate, including the first doubtful digit.

For example, the measurement "23.4 cm" has four significant figures, while "23.40 cm" has five significant figures.

Explanation

Evaporation is the process by which molecules escape from the surface of a liquid to become vapor, even if the liquid is below its boiling point.

This occurs when some molecules have enough energy to break free from the surface tension of the liquid and turn into vapor.

Key Points:

• Boiling occurs when a liquid is heated to its boiling point, causing bubbles to form and rise to the surface.
• Condensation is the process by which vapor is converted back into a liquid.
• Convection is the transfer of heat through the movement of fluids.

Explanation

Evaporation occurs when molecules on a liquid's surface gain enough energy to escape into the air, and this can happen at any temperature, not just at boiling point.

It's a slow process at lower temperatures, but faster at higher temperatures.